#!/usr/bin/perl

# VHDL Obfuscator
# Dave Stevens - D.Stevens@lboro.ac.uk

use POSIX;

if($#ARGV < 0)
{
    print<<ERROR;
You did not pass any arguments.
*required
-indir=<dir>   - directory of input files
-outdir=<dir>  - directory to output to
*optional
-l=<number>    - length of strings
-k=<file>      - file of words to not obfuscate
-h=<file>      - file of previous hashes
ERROR
exit(0);
}


srand(1234567);
$extension = "vhd";
#$entity = 1;
$str_len = 32;
$keyword_file = "";
$hash_file = "";

foreach $arg (@ARGV)
{
	if($arg =~ /-l=(\d+)/)
	{
	    $str_len = $1;
	}
	elsif($arg =~ /\-indir=(\/?((\w+)\/?)+)/i)
	{
		if($arg =~ /\/$/)
		{
			chop($arg);
		}	
		($none, $indir) = split(/=/, $arg);
		push @files, <$indir/*.$extension>;
	}
	elsif($arg =~ /\-outdir=(\/?((\w+)\/?)+)/i)
	{
		if($arg =~ /\/$/)
		{
			chop($arg);
		}
		($none, $outdir) = split(/=/, $arg);
	}
	elsif($arg =~ /-k=(.+)/)
	{
	    $keyword_file = $1;
	}
	elsif($arg =~ /-h=(.+)/)
	{
	    $hash_file = $1;
	}
}

if($outdir eq "")
{
	print "You haven't specified an Output Directory, please use the parameter -outdir=<dir>\n";
	exit(0);
}
if($indir eq "")
{
	print "You haven't specified an Input Directory, please use the parameter -indir=<dir>\n";
	exit(0);
 }

if($#files < 0)
{
	print "No Files Found: $indir\n";
	exit(0);
}

print "SETTINGS------------------------\n";
print "INDIR:   $indir\n";
print "OUTDIR:  $outdir\n";
print "KEYWORD: $keyword_file\n";
print "HASH:    $hash_file\n";
print "LENGTH:  $str_len\n\n";

# if out directory does not exist
if(!(-d($outdir)))
{
	system("mkdir $outdir");
}

&setup_delims("/,>=\"-+)':<&*(.;| 	");
&setup_keywords("left|right|is|file|entity|reject|e|constant|sll|linkage|severity|rem|access|open|group|impure|else|inout|configuration|case|generate|out|of|body|ror|bus|disconnect|others|for|next|sra|xnor|library|function|downto|begin|rol|attribute|block|x|on|register|nand|array|postponed|alias|use|report|buffer|guarded|package|not|xor|map|signal|if|loop|exit|to|subtype|nor|sla|all|component|until|end|b|and|pure|generic|abs|assert|srl|select|or|new|null|variable|label|unaffected|literal|when|procedure|record|units|process|inertial|return|then|architecture|transport|port|while|o|shr|shl|high|low|range|elsif|mod|type|shared|in|with|wait|after|integer|std_logic|std_logic_vector|ieee|work|std_logic_1164|std_logic_arith|std_logic_unsigned|std_logic_signed|numeric_std|signed|unsigned|std|textio|time|ns|ms|conv_std_logic_vector|natural|range|warning|failure|false|boolean|conv_integer|rising_edge|falling_edge|true|note|error|foreign|event|string");

# pull in the hashed file and the keyword file here!
if($hash_file ne "")
{
    # check if file exists
    if(-e($hash_file))
    {
	open HASH_FILE, "< $hash_file" or die "Could not open file: $hash_file ($!)\n";
	while( <HASH_FILE> )
	{
	    chomp();
	    ($string, $word) = split(/ => /);
	    if(defined($string))
	    {
		$hash_inp_str{uc($word)} = $string;
		$hash_str_inp{$string} = uc($word);
	    }
	}
	close HASH_FILE;
    }
    else
    {
	print "The hash file you specified: $hash_file does not exist\n";
	exit(0);
    }
}

if($keyword_file ne "")
{
    # check if file exists
    if(-e($keyword_file))
    {
	open KEYWORD_FILE, "<$keyword_file" or die "Could not open file: $keyword_file ($!)\n";
	while( <KEYWORD_FILE> )
	{
	    chomp();
	    $keywords{uc($_)} = 1;
	}
	close KEYWORD_FILE;
    }
    else
    {
	print "The keyword file you specified: $keyword_file does not exist\n";
	exit(0);
    }
}


foreach $file (@files)
{
    open IN_FILE, "< $file" or die "Could not open: $file : $!\n";
    @out_file = split(/\//, $file);
    open OUT_FILE, "> $outdir/$out_file[$#out_file]" or die "Could not open file: $outdir/$out_file[$#out_file] : $!\n";

    $in_a_string = 0;

    while( <IN_FILE> )
    {
	chomp();
	$_ =~ s/^\s+//g;
	($code, $comment) = split(/--/, $_);
	if($comment =~ /pragma/)
	{
	    print OUT_FILE "\n--", $comment, "\n";
	}

	if(defined($code))
	{
	    @words = split(/\s+/, $code);
	    foreach $word (@words)
	    {
		@chars = split(//, $word);
		$current = "";
		for($i=0;$i<=$#chars;$i++)
		{
		    if($in_a_string)
		    {
			for($j=$i;$j<=$#chars;$j++)
			{
			    print OUT_FILE $chars[$j];
			    if($chars[$j] eq '"')
			    {
				$in_a_string = 0;
				#this is the end;
				$i = $j+1;
				last;
			    }
			}
			if($j >= $#chars)
			{
			    print OUT_FILE " ";
			    last;
			}
		    }
		    
		    elsif($chars[$i] eq '"')
		    {
			
			if(defined($current) && ($current ne ""))
			{
			    if($keywords{uc($current)} == 1)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    elsif($current =~ /^\d+$/)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    elsif($current =~ /^\w+#\w+#$/)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    else
			    {
				print OUT_FILE &create_random_string($current);
				undef($current);
			    }
			}
			
			$in_a_string = 1;
			print OUT_FILE $chars[$i];
			for($j=$i+1;$j<=$#chars;$j++)
			{
			    print OUT_FILE $chars[$j];
			    if($chars[$j] eq '"')
			    {
				$i = $j+1;
				$in_a_string = 0;
				last;
			    }
			}
			if($j >= $#chars)
			{
			    print OUT_FILE " ";
			    last;
			}
		    }
		    
		    $current .= $chars[$i];
		    # check for delims
		    if($delim{$chars[$i]} == 1)
		    {
			$delim .= chop($current);
			if(defined($current) && ($current ne ""))
			{
			    if($keywords{uc($current)} == 1)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    elsif($current =~ /^\d+$/)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    elsif($current =~ /^\w+#\w+#$/)
			    {
				print OUT_FILE $current;
				undef($current);
			    }
			    else
			    {
				print OUT_FILE &create_random_string($current);
				undef($current);
			    }
			}
			print OUT_FILE $delim;
			undef($delim);
		    }
		}
		
		if(defined($current) && ($current ne ""))
		{
		    if($keywords{uc($current)} == 1)
		    {
			print OUT_FILE $current;
			undef($current);
		    }
		    elsif($current =~ /^\d+$/)
		    {
			print OUT_FILE $current;
			undef($current);
		    }
		    elsif($current =~ /^\w+#\w+#$/)
		    {
			print OUT_FILE $current;
			undef($current);
		    }
		    else
		    {
			print OUT_FILE &create_random_string($current);
			undef($current);
		    }
		}
		print OUT_FILE " ";
	    }
	}
#	print OUT_FILE "\n";
    }
    close IN_FILE;
    close OUT_FILE;
}


open HASHED, "> hashed.txt" or die;
while(($key, $value) = each(%hash_str_inp))
{
    print HASHED $key, " => ", $value, "\n";
}
close HASHED;

exit(0);

# setup @delim and %delim
sub setup_delims()
{
    @delims = split(//, $_[0]);

    foreach $del (@delims)
    {
	push @delim, "\\$del";
	$delim{$del} = 1;
    }
}

# setup %keywords
sub setup_keywords()
{
    @keywords = split(/\|/, $_[0]);

    foreach $keyz (@keywords)
    {
	$keywords{uc($keyz)} = 1;
    }
}

# create a random string
sub create_random_string()
{
    $inp = uc($_[0]);
    $str = "";

    # if one has already been created then use that
    if(defined($hash_inp_str{$inp}))
    {
	return $hash_inp_str{$inp};
    }
#    while(($key, $value) = each(%hash_inp_str))
#    {
#	if($key =~ /^$inp$/i)
#	{
#	    return $hash_inp_str{$inp};
#	}
#    }

    # create the new string
    for($_i=0;$_i<$str_len;$_i++)
    {
	#$str .= chr(int(rand(26)) + 97);
	$temp = int(rand(26+26+10));
	if($temp < 26)
	{
	    $str .= chr($temp + 97);
	}
	elsif(($temp >= 26) && ($temp < 52))
	{
	    $str .= chr($temp - 26 + 65);
	}
	else
	{
	    $str .= chr($temp - 52 + 48);
	}
    }

    if($str =~ /^(\d)/)
    {
	$temp = chr(ord($1) + 64);
	$str =~ s/^\d/$temp/;
    }

    # at this point if there are ay clashes they fail out.
    if(defined($hash_str_inp{$str}))
    {
	print "There has been a clash matey!\n";
	exit(0);
    }
    $hash_inp_str{$inp} = $str;
    $hash_str_inp{$str} = $inp;

    return $str;
}